YES We show the termination of the TRS R: le(|0|(),y) -> true() le(s(x),|0|()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,|0|()) -> x minus(s(x),s(y)) -> minus(x,y) mod(|0|(),y) -> |0|() mod(s(x),|0|()) -> |0|() mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) if_mod(false(),s(x),s(y)) -> s(x) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: le#(s(x),s(y)) -> le#(x,y) p2: minus#(s(x),s(y)) -> minus#(x,y) p3: mod#(s(x),s(y)) -> if_mod#(le(y,x),s(x),s(y)) p4: mod#(s(x),s(y)) -> le#(y,x) p5: if_mod#(true(),s(x),s(y)) -> mod#(minus(x,y),s(y)) p6: if_mod#(true(),s(x),s(y)) -> minus#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(x,|0|()) -> x r5: minus(s(x),s(y)) -> minus(x,y) r6: mod(|0|(),y) -> |0|() r7: mod(s(x),|0|()) -> |0|() r8: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r9: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r10: if_mod(false(),s(x),s(y)) -> s(x) The estimated dependency graph contains the following SCCs: {p3, p5} {p1} {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: if_mod#(true(),s(x),s(y)) -> mod#(minus(x,y),s(y)) p2: mod#(s(x),s(y)) -> if_mod#(le(y,x),s(x),s(y)) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(x,|0|()) -> x r5: minus(s(x),s(y)) -> minus(x,y) r6: mod(|0|(),y) -> |0|() r7: mod(s(x),|0|()) -> |0|() r8: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r9: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r10: if_mod(false(),s(x),s(y)) -> s(x) The set of usable rules consists of r1, r2, r3, r4, r5 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: if_mod#_A(x1,x2,x3) = max{6, x2 - 23} true_A = 4 s_A(x1) = max{20, x1 + 12} mod#_A(x1,x2) = max{5, x1 - 13} minus_A(x1,x2) = max{3, x1 + 1} le_A(x1,x2) = max{x1 + 1, x2 + 3} |0|_A = 20 false_A = 11 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: if_mod#_A(x1,x2,x3) = max{2, x1 - 19, x2 - 56, x3 - 45} true_A = 9 s_A(x1) = x1 + 46 mod#_A(x1,x2) = max{2, x1 - 56, x2 - 45} minus_A(x1,x2) = max{x1 + 40, x2 + 34} le_A(x1,x2) = max{x1 - 9, x2 + 9} |0|_A = 10 false_A = 20 if_mod#!_A(x1,x2,x3) = max{1, x1 - 6, x2 - 93, x3 - 43} true!_A = 13 s!_A(x1) = x1 + 4 mod#!_A(x1,x2) = 2 minus!_A(x1,x2) = max{5, x1 - 47} le!_A(x1,x2) = max{58, x2 + 12} |0|!_A = 0 false!_A = 58 partial status: pi(if_mod#) = [] pi(true) = [] pi(s) = [1] pi(mod#) = [] pi(minus) = [] pi(le) = [1] pi(|0|) = [] pi(false) = [] The following rules are removed: p1, p2 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: le#(s(x),s(y)) -> le#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(x,|0|()) -> x r5: minus(s(x),s(y)) -> minus(x,y) r6: mod(|0|(),y) -> |0|() r7: mod(s(x),|0|()) -> |0|() r8: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r9: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r10: if_mod(false(),s(x),s(y)) -> s(x) The set of usable rules consists of r1 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: le#_A(x1,x2) = 1 s_A(x1) = 2 le_A(x1,x2) = max{5, x1 - 4, x2 - 4} |0|_A = 1 true_A = 3 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: le#_A(x1,x2) = max{x1, x2} s_A(x1) = max{6, x1 + 1} le_A(x1,x2) = max{2, x1 - 7, x2 - 7} |0|_A = 6 true_A = 0 le#!_A(x1,x2) = max{3, x1 - 2, x2 - 7} s!_A(x1) = 2 le!_A(x1,x2) = max{5, x1 - 14, x2 - 7} |0|!_A = 1 true!_A = 3 partial status: pi(le#) = [] pi(s) = [] pi(le) = [] pi(|0|) = [] pi(true) = [] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(x,|0|()) -> x r5: minus(s(x),s(y)) -> minus(x,y) r6: mod(|0|(),y) -> |0|() r7: mod(s(x),|0|()) -> |0|() r8: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r9: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r10: if_mod(false(),s(x),s(y)) -> s(x) The set of usable rules consists of r1 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: minus#_A(x1,x2) = max{7, x1 - 7, x2 - 16} s_A(x1) = max{15, x1 + 6} le_A(x1,x2) = max{4, x1 - 16, x2 - 16} |0|_A = 2 true_A = 3 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: minus#_A(x1,x2) = max{x1, x2} s_A(x1) = max{3, x1 + 1} le_A(x1,x2) = max{2, x1 - 4, x2 - 3} |0|_A = 2 true_A = 0 minus#!_A(x1,x2) = max{8, x1 - 4, x2 - 20} s!_A(x1) = max{7, x1 - 19} le!_A(x1,x2) = max{4, x1 - 18, x2 - 10} |0|!_A = 2 true!_A = 3 partial status: pi(minus#) = [] pi(s) = [1] pi(le) = [] pi(|0|) = [] pi(true) = [] The following rules are removed: p1 Then no dependency pair remains.